High resolution unsaturated alkenones sea surface temperature records in the Yellow Sea during the period of 3500–1300 cal. yr BP

Abstract High-resolution sea surface temperature records based on long-chain unsaturated alkenones ( U 37 K ′ -SST) in the south Yellow Sea (YS) during the period of 3500–1300 cal. yr BP were reconstructed in sediment core Z8 from the Shandong mud wedge. The SST records show broad variations between 14.3 and 16.9 °C (15.6 °C on the average), with a high SST phase at 3500-2750 cal. yr BP, a low and intense fluctuating SST period at 2500-2000 cal. yr BP and a sharp cooling period at 1750-1300 cal. yr BP. Superimposed on this trend, five cooling periods occurred in 3360–3250 cal. yr BP, 3150–3050 cal. yr BP, 2750–2650 cal. yr BP, 2350–2150 cal. yr BP, and 1750-1300 cal. yr BP. Variation pattern of the SST records is similar to the fluctuations of the Kuroshio Current (KC), indicating a close relationship between the Yellow Sea Warm Current (YSWC) and the KC. The general U 37 K ′ -SST curve fluctuates with the local air temperature variations. The intensity of the East Asia Winter Monsoon (EAWM) could be a key factor affected the prevailing relationship between the cold coastal current and the warm YSWC, and dominated the SST variation in core site Z8 during 3500–1300 cal. yr BP. Furthermore, our temperature records, within age uncertainty, coincides with the changes of the solar irradiance changes, suggesting a possible link between solar forcing and climate variability.